Switching device for party-line exchanges.



W. HAGSTROM. SWII'GHING DEVICE FOR PARTY LINE EXCHANGES.

APPLICATION FILED JUNE 11, 1906.

909,403. Patented Jan. 12, 1909.

2 SHEETSSHEET 1.

W. HAGSTROM. SWITCHING DEVICE FOR PARTY LINE EXCHANGES. APPLICATION FILED JUNE 11, 1906.

909,403. I I Patented Jan. 12,1909.

2 SHEETS-SHEET 2.

E El- 2 I MEI is) if K I I I f w' l WILLIAM HAGSTROM, OF LINDSBORG, KANSAS, ASSIGNOR, BY DIRECT AND MESNE ASSIGN- MENTS, OF ONE-FOURTH TO JOHN ANDERSON AND ONE-FOURTH TO CLARENCE A. ANDER- SON, OF SALINA, KANSAS.

SWITCHING DEVICE FOR PARTY-LINE EXCHANGES.

Specification of Letters Patent.

Fatented Jan. 12, 1909.

To all whom it may concern:

Be it known that I, WILLIAM I'IAGSTROM, a citizen of the United States of America, and a resident of Lindsborg, county of McPherson, and State of Kansas, have invented certain new and useful Improvements in Switching Devices for Farty Line EX- changes, of which the following is a specification.

My invention relates to switching devices for party line exchanges and has for its obj ect improvements in such devices.

In the accompanying drawings, Figure 1 is a front elevation of the device in its normal position; Fig. 2 is a similar elevation with the device moved to the position in which it connects its station telephonically to the party line; Fig. 3 is a similar elevation with the device moved to the position from which it may be released so that it may return to its normal position; Fig. 4 is a side elevation of Fig. 1; Fig. 5 is a detail being partial bottom view of Fi 1; and Fig. 6 is a detached view of some of the operating parts in the same position as Fig. 1.

In the said drawings A is a magnet having a polarized armature and lever B, on the end of which is a pawl O adapted to engage a ratchet wheel D to move it. A holding pawl E prevents a return of the wheel to normal position until released, which return is accomplished by a spring F.

The parts so far described, do not differ in essence from devices already well known, but I believe that it will add to clearness for me to describe at this point the particular functions which the device is intended to perform, and from which the novel features may be more readily understood. In party line telephone exchanges of the type to which this invention pertains there is a telephone line leading from a central office to a series of local stations. At each local station there is a switching device of some kind, the object of which is to place the station in telephonic connection with the line. These devices are operated simultaneously by impulses sent over the line by an operator at the central oflice. In what is commonly known as the look-out system these de vices are arranged to close electrical connections successively to associated magnets. Adjacent to each of these magnets is some form of contact closing device operated by the magnet, and also some means for holding the contact closing device closed after being operated and until released by the operator at the central oflice. These associated magnets have a circuit used by the operator for operating the switching mechanisms, and should she choose to send an impulse over this independent circuit at the time when any particular associated magnet is connected thereto by its switching mechanism, the station at which the operated magnet is located will be connected telephonically to the line but other stations will not be so connected. Ordinarily the switching mechanisms are advanced by impulses flowing in one direction over the line and are released by an impulse in the other direction.

The object of my invention is to produce a mechanism which will perform all of the useful functions of the ordinary switching mechanism and its associated magnet, and yet will at the same time dispose of that magnet and its circuit. I accomplish this result within the switching mechanism itself but it should be remembered that the switching mechanism to erform its function must be associated wlth other similar switching mechanisms at other stations and all connected to a central ofiice by means of a party line.

Returning now to the description of the mechanism, there is attached to the frame work a bracket G on which are two vertically slidable pieces II and 5 which normally fall by gravity to the position shown in Figs. 1 and 6. On the wheel D is a pin K arranged to strike and raise the slide J when the mechanism is moved to its extreme forward position. On the spindle of the wheel D is an arm L arranged to strike a pin M on the slide H and to raise that slide at some predeter mined time between the first and last movements of the wheel D. In a party line having a series of stations the rise of the slide H occurs at station No. 1 just before it occurs at station No. 2; at station No. 2 just before station No. 3; and so on. This result is accomplished by adjusting the arms L of the different stations so that in normal position they will be different distances from the pin M. The slide H is made so as to be capable of comparatively long movement while the slide J is capable of only a short movement.

On the driving pawl O is a laterally projecting pin C which has a thin edge normally adjacent to and just above a similar thin edge projecting laterally from the upper end of the slide J. 'i he pawl U moves to either the left or the right of its normal position (Figs. 1 and 6) according to the direction of the impulses sent through the magnet A. W hen the switching mechanism is operated to advance it the pin U moves away from, and consequently does not strike, the upper end of the slide J. normal (lowest) position, a movement of the pawl C in the opposite direction causes the thin edge of the pin U to pass over the upper hooked end of the slide J. lint when the pin K has struck the slide J and has moved it upward, a backward movement (toward the right) of the pawlC causes the pin to engage the hook on the upper end of slide J and turn that slide pivotally on the screw stud upon which it slides vertically. \"t hen the pawl C moves backward it slides over a fixed pin shown just below the pin U, and in sliding over this pin it rises clear of the ratchet wheel D. On the upper end of the holding pawl E is a pin which normally rests against the back face of the slide J. V\' hen the slide J has been raised and a backward movement of the pawl (l moves the said slide backward, the slide in turn presses the pin on the pawl E backward and thus raises the holding pawl also from engagement with the wheel In this condition the spring l? is free to return the wheel to its normal position, and this return withdraws the pin K and arm L from under the slides J and H and permits these slides to fall by gravity to their normal posi tion.

On the armature lever B is a lateral arm terminating in a thin projection B which normally lies adjacent to and slightly above a laterally projecting hook on the upper end of the side H. When the slide His in its v normal positon a backward movement of the armature lever causes the projection B to pass idly over the hook on the upper end of the slide H, but after the said slide has been raised a predetermined number of steps by reason of contact between the arm L and the pin M,then a backward movement of the armature lever causes the projection B to strike the hook on the upper end of the slide H and turns that slide pivotallyupon the screw stud upon which it normally slides. If the slide H has been moved upward more than the predetermined number of steps, then a backward movement of the armature lever causes the projection B to pass idly under the hook on the upper end of the slide H. The number of predetermined upward steps of the slide H before the hook thereon is in position to be engaged by the projection B is usually one, though it may be any desired number, and does not need to be the same number in all the switching mechanisms connected to the same party line. Ad-

"W hen the slide J is in its justment of the arm L has hereinbefore been stated as the means for bringing the slides H of different mechanisms successively to position tobe engaged by the, projection B but that result may be partly accomplished by such adjustment and partly by making the slides 11' or the projections B so that difl'erent numbers of vertical steps will be required.

Pivoted at a convenient place is a bellcrank lever N one arm of which projects horizontally along the bottom of the mechanism and the other arm of which projects vertically back of the silde H. On the side of the vertical arm is a projection which normally rests, by reason of the gravity of the horizontal arm, against the back of the upper end of the slide H. Also on the upper end of the vertical arm of the lever N is a piece of insulation which is adjacent to one of a series of contact springs P. These springs are normally not in electrical connection with each other, but when a backward movement of the armature lever B causes a similar backward movement of the slide H, the movement of the slide H causes a movement of the lever N to close the springs P together as shown in Fig. 2. V

Pivoted at another place on the frame work of the mechanism is an arm R the free end of which has a hook adjacent to the free end of the horizontal part of the lever N. When the wheel D is in its normal position a pin S therein engages the arm R and keeps its hook clear of the lever N, but as soon as the wheel D has moved forward one step the pin Sleeves the arm R. If thereafter the lever N be moved to close the springs P as previously described, the hook on the arm R engages the lever N to hold this connection as shown in Figs. 2 and 3. When the wheel returns to its normal position the pin S strikes the arm R andreleases it from the it will be apparent to those familiar with party line exchanges that when the operator sends impulses in an operating direction over the line all of the switching mechanisms connected thereto will be simultaneously advanced step by step, and that no impulse in the reverse direction will be effective to release the mechanisms until after they have been moved to the limit of their forward movements. It will also be seen by the preceding description that the non-releasing effeet of reverse impulses during intermediate portions 01" the forward movement is utilized to enable the switch operating magnet to also operate the locking-in connections.

In addition to the parts so far described the mechanism contains certain other devices not directly connected with invention herein sought to be claimed. Thus, there is a contact spring T which is in electrical connection with the wheel D when at normal position, and a second contact spring V which is in electrical connection with the wheel when at its extreme forward movement. As these are related to the circuits used in the party line connections rather than to the switching mechanism, they need no special description.

Assuming the switching mechanism connected to a party line in the ordinary way and the device to be in its normal position, the first operating impulse sent over the line advances the ratchet wheel D one step. This causes the pin S to leave the arm it so that the catch thereon is ready to catch and hold the bell-crank N whenever raisedv After a predetermined number of steps the arm L engages the pin M to raise the slide E. If a reverse impulse (commonly called a release impulse) be sent through the magnet A at the time the hook on the upper end of slide H is opposite the projection 13, the backward movement of the armature will strike this hook and cause the slide H to turn on its point. This movement of the slide H will be communicated to the bell-crank N to raise its lower end so that it will be caught and held in its raised position by the catch lever R. In this condition the bell-crank N closes the electrical connecting springs P as described. if a reverse impulse be not sent at this particular time the projection B moved backward at any other time will not operate the bell-crank N. After a further predeter mined number of operating impulses have been sent, the pin K strikes and raises the slide J, bringing its upper end opposite the pin 0 Upon a reverse impulse being sent at this time the pin C will strike and move backward the slide J, and this slide will in turn strike and raise the holding pawl E. As the driving pawl is also freed from the ratchet wheel by this backward movement, the wheel is free to be returned to its normal position by the spring F. In returning to normal position the pin K arid arm L permit the slides H and J to fall back to normal position. The pin S also strikes the lever R to release the bell-crank N, provided that bell crank had been caught and held as described.

N hat I claim is 1. The combination with a switching mechanism, a releasing device therefor, and a telephone connecting device, of a magnet arranged to move its armature in either of two directions according to the direction of the impulses sent therethrough, means by which a movement of the armature in one direction serves to advance the switching mechanism step-by-step, means by which both the connecting device and the releasing device are operated by movements of the armature in the reverse direction, and means controlled by the advance movement of the switching mechanism for bringing the connecting device and the releasing device into operative relationship to the armature at different times.

2. The combination with a connecting mechanism, a selecting mechanism therefor, and means by which said mechanisms are returned to normal position when released, of a magnet, and connections operated thereby and so arranged that impulses sent through said magnet serve to successively operate the selecting mechanism, the connecting mechanism and the release for said mechanisms.

3. The combination with a switching mechanism, and a magnet provided with an armature for advancing it, of a telephone connecting device and releasing devices both arranged to be operated by a reverse movement of the armature and both normally disconnected therefrom, and interposing devices moved by the advance of the switching mechanism so as to bring the connecting device and the releasing devices into operative connection with the armature at different times.

4:. The combination with contact devices by which a telephone station is placed in or excluded from telephonic connection with a party line, a selecting mechanism, and devices for releasing the contact devices and the selecting mechanism after being operated, of a magnet, and means by which said magnet serves to successively operate the selecting mechanism, the contact devices, and the releasing devices.

5. The combination with a magnet and armature lever therefor, a switching mechanism operated by the magnet, .a normally open telephonic connection, and devices for releasing the switching mechanism after being operated, of a device moved by the switching mechanism and serving to place the telephonic connection temporarily in operative relationship with the armature lever, and a separate device also moved by the switching mechanism and serving to place the releasing devices in operative relationship with the armature lever.

6. The combination with a step by step mechanism, and a magnet for advancing it from its normal position, of a telephone connecting device normally not in operative relationship with said magnet, a releasing device for said mechanism also normally not in operative relationship with said magnet,

means controlled by said mechanism for 'placmg the connecting device in operative tive relationship with the magnet at a predetermined later step of said mechanism.

7. The combination with a magnet, and a normally open telephonic connection normally not in operative relationship with said magnet, and of a step by step mechanism operated by said magnet, and a device moved by said mechanism and serving to connect said magnet and-said telephonic connection in operative relationship with each other.

8. The combination with a switching mechanism, a magnet provided with an armature for advancing it, a telephone connecting device, and releasing devices for said switching mechanism, of devices moved by the advance of the switching mechanism and so arranged as to bring the connecting device and the releasing devices at diflerent times into mechanically operative relations with the armature.

9. The combination with a magnet, and a step by step mechanismoper e yvs magnet when impulses flow therethrough in a given direction, of a telephonic connection and releasing devices arranged to be operated by said magnet when impulses flow therethrough in a reverse direction but normally not in a condition to be so operated, and devices moved by said mechanism and arranged to be interposed successively be tween said magnet and said telephonic connection and between said magnet and said releasing devices so that they may be operated by said magnet.

10. The combination with a movable lever, and a contact mechanism, of means by j which the normal movement of the lever serves to bring the lever and the contact mechanism into temporary operative relationship to each other, and means by which areverse movement of the lever at such time actuates the contact mechanism.

' Signed at Chicago, 111., this 8th day of 

